Add information showing lack of efficacy of Oxford/AstraZeneca agains…

…t the SA variant

Adding the preprint, Oxford's press release-ish article on the matter, and ScienceMag detailing of South Africa no longer rolling out the vaccine; should later add information about SA seeking to use J&J instead

README.md

@@ -324,6 +324,7 @@ Note that the WHO will generally be unable to make statements that their more pr
 * [Pascal Soriot: "There are a lot of emotions on vaccines in EU. But it's complicated"](https://www.repubblica.it/cronaca/2021/01/26/news/interview_pascal_soriot_ceo_astrazeneca_coronavirus_covid_vaccines-284349628/) is an extensive interview with the CEO of AstraZeneca discussing the reduced number of vaccine doses expected to be initially delivered to the EU, with some countries threatening legal action over failure to meet contractual obligation, and the interview also covers many specifics on vaccine production and testing
 * [Contract between European Commission and AstraZeneca now published](https://ec.europa.eu/commission/presscorner/detail/en/ip_21_302), after pressure from the European Commission, albeit with a number of redactions
 * [Efficacy of ChAdOx1 nCoV-19 (AZD1222) Vaccine Against SARS-CoV-2 VOC 202012/01 (B.1.1.7)](https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3779160) finds that while virus neutralization activity is 9-fold lower in the B.1.1.7 variant than in the "common" virus, the vaccine was similarly efficacious in preventing symptomatic COVID-19 in both variants
+* [Safety and efficacy of the ChAdOx1 nCoV-19 (AZD1222) Covid-19 vaccine against the B.1.351 variant in South Africa](https://www.medrxiv.org/content/10.1101/2021.02.10.21251247v1) concludes that the vaccine did not show protection against the variant in mild to moderate cases, while protection against severe cases remains undetermined due to the study participants who became positive to the virus being small numbers, and young and healthy, with no hospitalizations or deaths necessarily expected in any case; the University of Oxford announces these results, stating that [ChAdOx1 nCov-19 provides minimal protection against mild-moderate COVID-19 infection from B.1.351 coronavirus variant in young South African adults](https://www.ox.ac.uk/news/2021-02-07-chadox1-ncov-19-provides-minimal-protection-against-mild-moderate-covid-19-infection#), and in response, [South Africa suspends use of AstraZeneca’s COVID-19 vaccine after it fails to clearly stop virus variant](https://www.sciencemag.org/news/2021/02/south-africa-suspends-use-astrazenecas-covid-19-vaccine-after-it-fails-clearly-stop)
 
 
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